Apparatus for counting revolutions within a predetermined speed range



I Feb. 17,-1970 RQVJOVFIANSQN I 1 armmus .Fon coun'rme nmvowmous wrmm A PREDETEBMINED SPEED RANGE Filed June' 27, 1966 :5 Sheets-Sheet 1 mxme I r-REVOLUTIONS 1 COUNTER I e-ssgouo l DELAY 4 I CIRCUIT I TOTAL I REVOLUTIONS ggs I COUNTER I 29 l5 SECOND I INDICATOR DELAY :5 E. LAMP CIRCUIT INVENTOR. i FREDERIC R. JOHANSON 34 4 I BY MAHONEY, MILLER 8 RAM ATTORNEYS Feb. 17, 1970 FR. JOHANSON v APPARATUS FOR COUNTING REVOLUTIONS WITHIN A PREDETERMINED SPEED RANGE Filed Ju ne 27 1966 3 Sheets-Sheet 2 v INVENTOR. F RE DE RIC R. JOHA NSON M. m m R M a M R T E T I. 1A M 0 U My MB M mm g F. R. J'oHANsoN Feb. 17 1970 I I 3,496,343

APPARATUS FOR COUNTING REVOLUTIONS WITHIN A PREDETERMINED SPEEDRANGE 3 Sheets-Sheet 3 Filed June 27, 1966 INVENTOR. FEEDER/C R. JOHANSON M m A E R. N a m m w LVA H N Y MB M United States Patent Office 3,496,343 APPARATUS FOR COUNTING REVOLUTIONS WITHIN A PREDETERMINED SPEED RANGE Frederic R. Johanson, Columbus, Ohio, assignor to The Jaeger Machine Company, Columbia, Ohio, :1 corporation of Ohio Filed June 27, 1966, Ser. No. 560,776 Int. Cl. G06f 7/38 US. Cl. 235-92 11 Claims ABSTRACT OF THE DISCLOSURE A counter apparatus is provided for cumulatively recording the number of recurrent motion cycles. The apparatus includes a sensor for detecting the cyclic motion of a mechanism and circuit means responsive to the sensor and operative to discriminate between motion cycles occurring within a specified frequency range for cyclic rate and those motion cycles which occur at a greater or lesser rate. A counter-type output device connected to the circuit means provides a visual display of the number of motion cycles within the specified range.

General background of the invention There are numerous industrial applications where a counter apparatus is desired or necessary to provide recorded data as to the number of recurrent motion cycles. It is often required that this data be discriminatory as to motion cycles having a frequency or rate of recurrence within a predetermined range or limitation. A primary example of such an application, and the application for which the disclosed apparatus was specifically designed, is in the ready-mix concrete industry. To obtain concrete which is of uniform quality and is capable of attaining the designed structural characteristics, it is essential that the concrete forming materials be'mixed to a specified and predetermined degree. The mixing is of particular importance as mixing to a greater or less degree than that which is desired will have a substantial detrimental effect on the quality and uniformity of the concrete. In the ready-mix concrete industry, the agitation and mixing operations are performed in transit from a batching plant supplying the segregated materials to the utilization site by the well known truck-mounted mixers and the degree of agitation and mixing is related to the peripheral speed of the mixer drum. Accordingly, the maximum and minimum peripheral speed of a particular mixer drum may be specified to assure that the mixing operation will produce concrete of an acceptable quality. Since the peripheral speed of a particular mixer drum is related to its rotational speed, the peripheral speed may be conveniently expressed in terms of maximum and minimum revolutions per minute with each revolution being referred to hereinafter as a motion cycle. It is difficult to accurately control the mixer operation and, since the transit time of the ready-mix trucks is of a relatively indefinite and indeterminate nature, means must be provided for monitoring the mixer operation to provide the necessary information for determination of the acceptability of the concrete.

Heretofore, apparatus has been developed for utilization with the ready-mix type concrete trucks to provide in- 4 formation as to the total number of revolutions of the mixing drum and as to the number of revolutions which are above a predetermined rate or frequency for ascertaining the acceptability of the concrete. Such prior art apparatus as is known, however, does not discriminate as to motion cycles which are recurring at a rate greater than a predetermined maximum frequency. Recurrent 3,496,343 Patented Feb. 17, 1970 motion cycles which are above or below the predeter-' mined maximum or minimum rate for the mixing operation are not effective in obtaining a desired uniform concrete mix of specified quality.

It is, therefore, the primary object of this invention to provide a counter apparatus which is capable of providing recorded data as to the number of motion cycles which are recurring at a frequency within a predetermined range.

It is a further object of this invention to provide a counter apparatus which is capable of providing recorded data. as to the total number of recurrent motion cycles, irrespective of their frequency and also recorded data as to the number of recurrent motion cycles within a predetermined frequency range.

It is another object of this invention to provide a counter apparatus for determining recurent motion cycles which are within a predetermined frequency range and which incorporates a motion cycle sensor of the noncontacting, magnetically-actuated type for detecting cyclic motion.

It is also an object of this invention to provide a counter apparatus for determining recurent motion cycles within a predetermined frequency range which is of simple, rugged construction and is reliably operable with a high degree of accuracy.

These and other objects and advantages of this invention will be readily apparent from the following detailed description of an embodiment thereof and the accompanying drawings.

In the drawings:

FIGURE 1 is a vertical, side-elevational view of a ready-mix concrete truck provided with a counter apparatus of this invention.

FIGURE 2 is a block diagram of the counter apparatus.

FIGURE 3 is a schematic diagram of the electrical circuit of the counter apparatus.

FIGURE 4 is a perspective view of the assembled counter apparatus exclusive of the sensor means.

Having reference to FIGURE 1, a counter apparatus 10 and associated sensor means 11 with a magnetic actuating device 12 is shown mounted on a ready-mix concrete truck chassis denoted generaly at 13. Carried by the truck chassis 13 is a mixing drum 14 which is supported for revolution about a slightly inclined longitudinal axis 14a by a roller structure. 15 and a front stand 16. A driving means is also provided for revolving the drum 14 at a predetermined rate or frequency with each revolution being a motion cycle and includes an engine 17 which is drivingly coupled to the mixing drum 14 through a chain 18 which engages a gear structure carried on the drum head 19 of the mixing drum 14. Suitable power transmission and control apparatus (not shown) may also be provided to permit selective operation of the drum 14 at a desired speed. The counter apparatus 10, exclusive of the sensor means 11, is preferably mounted in the operators cab of the truck chassis for convenience of the operator and an inspector who notes the recorded information as to the number of revolutions of the mixing drum. A suitable electrical cable 20 interconnects the major electronic components of the counter apparatus 10 with the sensor means 11 mounted on the front stand 16 in close proximity to the drum head 19. The magnetic actuating device 12 is mounted on the drum head 19 in such a position that, for each revolution of the drum 14, the device will pass the sensor means 11 and result in actuation of the counter apparatus 10 for recordation of a motion cycle.

As can be best seen by reference to FIGURE 4, the components of the counter apparatus are assembled in a suitable enclosure 21 having two visual numeric counters 22 and 23 which display the data as to the total number of drum revolutions and the number of drum revolutions which occur at a rate or frequency within a predetermined range for optimum mixing. These visual indicating counters 22 and 23- may be of any suitable type although the counters illustrated are of the revolving wheel type and which are actuated by an electrically operated solenoid. Also incorporated in the counter apparatus and mounted on the enclosure 21 is an indicator lamp 35 which provides additional visual indication of operation within the prescribed limits for a mixing operation. Attached to the exterior of the enclosure 21 is an adjustable type mounting bracket 24 which may be readily secured to a suitable supporting stmcture within the operators cab of the truck chassis to support the apparatus at a convenient location. In the installation illustrated in FIGURE 1, the apparatus is mounted on the dashboard 25 of the truck chassis 13.

In accordance with this invention, the counter apparatus 10 is designed to discriminate as to those motion cycles or revolutions of the drum 14 which are within a predetermined rate or frequency range and also indicate the total number of recurrent motion cycles. To accomplish this objective, the counter apparatus includes electrical circuit means, to be described in detail hereinafter, which is interconnected with counter means such as the mixing revolutions counter 23 and the sensor means 11 which determines the occurrence of a motion cycle. This circuit means is illustrated in simplified block diagram form in FIGURE 2 and illustrates the basic components of the circuit means. Electrical power for operation of the circuit means including the revolutions counters 22 and 23 may be obtained from any suitable power source and may include the conventional type of battery 26 which is carried on a truck chassis for the operation of the truck itself. Accordingly, a battery 26 is shown as the source of electrical power and is connected to the circuit means through the sensor means 11.

Operation of the mixing revolutions counter 23 is controlled by means of switch devices 27 and 28 (see FIG- URE 2) actuated by respective electronic timing circuits and incorporated in the circuit means. The electronic timing circuits include a fifteen-second delay circuit 29 and a six-second delay circuit 30 which are operatively connected to the respective switching devices 27 and 28. Each timing circuit is designed to determine the elapse of a predetermined time interval after initiation of a motion cycle and effect operation of the respectivezswitching devices after elapse of the specified time interval. The specific delay times are determined by the specified acceptable range of peripheral speed or frequency or rate of revolution of the mixing drum 14 during a mixing operation. The two delay circuits 29 and 30 are accordingly designed for determining time intervals associated with the slowest and fastest acceptable rates of revolution for the particular mixing drum 14. In this illustrated embodiment, the fifteen-second delay circuit 29 is associated with the lowest aceptable rate of revolution of 4 r.p.m. and the six-second delay circuit is associated with the highest aceptable rate of revolution which is 10 r.p.m. Also included in the circuit means is a reset circuit 31 which is operative to initiate operation of the delay circuits 29 and 30 and to return the delay circuits to an initial state of operation during the course of operation of the apparatus. Additional counter means is incorporated in the circuit means for recording the total revolutions of the mixing drum 14 and is identified herein as the total revolutions counter 22. The function of the electronic timing circuits 29 and 30 in the counter apparatus is to control operation of the switching devices 27 and 28 to permit application of a voltage signal, produced by the sensor means 11 at the conclusion of each motion cycle, to the mixing revolutions counter 23 at only those times which are associated with a motion cycle or drum revolution which is of a frequency within the prescribed range of operation. An indicator lamp circuit 34 is also incorporated in the circuit means for controlling the operation of the indicator lamp 35.

The sensor means 11 comprises a normally-open set of electrical contacts which are selectively closed in response to the proximate location of the magnetic actuating device 12 to thesensor means. This proximate actuating position of the magnetic device 12 occurs once each revolution of the mixing drum 14 as the magnetic device is mounted on the drum head 19 and is revolved past the sensor means 11 mounted on the front stand 16. This revolving movement of the magnetic actuating device, 12 is diagrammatically illustrated in FIGURE 2 with the axis of revolution indicated at 1411. As the magneuc uev1ce 12 passes in close proximity to the contacts of the sensor means 11, the contacts will momentarily close and complete an electrical circuit from the eletrical power source 26 to the electronic timing circuits 29 and 30 and to the mixing revolutions counter 23, if Within the prescribed time interval. This momentary closing of the contacts produces a voltage signal which is of pulse form.

At the time of initiating operation of the apparatus, the switch devices 27 and 28 would be in an open, nonconducting state and the application of a voltage signal pulse, as produced by passage of the magnetic device 12 in proximate relationship to the sensor means 11, to the electronic timing circuits at the initiation of a motion cycle would not be recorded by the mixing revolutions counter 23. This initiation voltage signal pulse, however, is effective in resetting the delay circuits 29 and 30 to an initial state of operation for determining a subsequent time interval and results in closing the switch devices 27 and 28. This signal pulse is of a relatively short duration as determined by the rate of passage of the magnetic actuating device 12 pass the contacts of the sensor means 11.

Resetting of the delay circuits 29 and 30 to an initial operating state for determining a subsequent time interval results in closing of the switching devices 27 and 28 for completing an electrically conductive path through the respective device to either effect actuation of the mixing revolutions counter 23 or to shunt the voltage signal pulse to an electrical ground which is connected to the electrical power source battery 26. At this state of the operation with the switching devices 27 and 28 in a closed position, a second or subsequent voltage signal pulse resulting from a first subsequent closure of the contacts of the sensor means 11 at the conclusion of the succeeding drum revolution and occurring prior to elapse of a sixsecond time interval will be ineffective in actuating the mixing revolutions counter 23 to record an operational cycle. This subsequent voltage signal pulse is shunted to ground through the switch device 28 which accordingly bypasses the mixing revolutions counter 23. To prevent excessive current drain on the battery-type power source 26, a current-limiting resistor R1 is connected in series between the contacts of the sensor means 11 and the switching devices 27 and 28. The subsequent signal pulse, however, is efiective in actuating the total revolutions counter 22 and actuating the reset circuit 31.

Operation of the reset circuit 31 again returns each of the delay circuits 29 and 30 to the initial state of operation of the circuits for determining a subsequent time interval. Should a second subsequent voltage signal pulse occur at a time after the six seconds have elapsed since initiation of the operational cycle, the switch 28 will be returned to an open circuit condition. The six-second delay circuit 30 will have operated to release the switching device 28 to this open circuit condition. Thus, the second subsequent voltage signal will be able to actuate the mixing revolutions counter 23 since the switching device 27 will be maintained in its closed circuit configuration. At the same time, the signal will be applied to the total revo lutions counter 22 and to the reset circuit 31 for recording a total revolutions count and for resetting the circuit for initiation of a subsequent timing cycle. In addition to operation of the mixing revolutions counter 23, the second subsequent voltage signal will be effective in causing the indicator lamp circuit 34 to function resulting in illumination of the indicator light 35. 1

Should the second subsequent voltage signal pulse occur after fifteen seconds have elapsed since initiation of the timing cycle, the fifteen-second delay circuit 29 will also have operated to release its respective switching device 27 to an open circuit, nonconducting state and the voltage signal pulse occurring after fifteen seconds will, therefore, be ineffective in operating the mixing revolutions counter 23 or the indicator lamp 35. Again, however, the signal pulse will be effective in operating the total revolutions counter 22 for recording a cycle of motion and for actuating the reset circuit 31 returning the respective delay circuits 29 and 30 to their initial state of operation with the switching devices 27 and 28 being in a closed circuit, electrically conducting state.

Thus, it will be readily seen that the circuit means of this counter apparatus is effective in selectively recording the number of motion cycles, as determined by the sensor means, which are of a frequency within a predetermined range and for visually indicating such cycles by the indicator lamp. Also, the apparatus provides a record of the total number of revolutions or motion cycles without discrimination as to frequency thereby providing complete information as to the process being monitored.

A detailed schematic diagram of the electrical circuit of the counter apparatus is shown in FIGURE 3 and described hereinafter to provide a more detailed explanation of the advantageous operation of the counter apparatus of this invention. Portions of the circuit are enclosed in broken lines and identified with the appropriate numerals relating to the major components of the apparatus as described in FIGURE 2. Only the electrically operated actuating elements of the indicating counters 22 and 23 are shown to illustrate the incorporation of the units in the circuit as the specific construction and mechanical operation of such counters is well known. Each counter 22 and 23 is actuated through cyclic energization of an actuating solenoid L1 and L2. The operation of the specific counters utilized in the present embodiment of the counter apparatus requires energization of the respective solenoid L1 or L2 with subsequent deenergization to effect a counting operation. In this circuit the coils of solenoids L1 and L2 are selectively connectable in circuit with the power source 26 by means of electronic switching apparatus which is effective in completing a circuit through the respective coil resulting in the energization thereof. A semiconductor rectifier device or diode, CR1 or CR2, is connected in shunt relationship to the respective solenoid coil, L1 or L2, to reduce the inductive voltage surge which results from operation of the electronic switching apparatus in disconnecting the respective coil from the power source 26 as each coil L1 and L2 is permitted to discharge through the respective shunt-connected semiconductor rectifier device.

As previously indicated, the electrical power for operating the counter apparatus is obtained from the battery 26 of the truck chassis. The usual power source of this type has a normal nominal voltage of about 12 volts although the actual voltage of a fully charged battery will approximate 13.6 volts. This voltage is suflicient for operation of the solenoid coils L1 and L2 through direct connection therewith and for powering a transistorized control circuit. A single-pole, manually operated switch device may be connected in series with the battery 26 to prevent operation of the circuit unless the switch is in a closed configuration. This switching device 33 may be advantageously incorporated in the conventional ignition switch with which the truck chassis is normally provided. As the six-second and fifteen-second delay circuits 30 and 29 must accurately determine a time interval, it is necessary that the power supply voltage of each be maintained at a relatively constant magnitude. This is effected by a voltage regulator circuit comprising a Zener diode CR3 and a series-connected, current-limiting resistor R2 which are selectively connectable across the output terminals of the battery 26 through the switch 33. In the present embodiment of the present apparatus, the Zener diode CR3 is of a type which maintains a relatively constant voltage of 8.2 volts at the junction of the Zener diode and its current-limiting resistor R2 and forms the B-plus power supply for the delay circuits.

The electronic switching apparatus, indicated generally by the numeral 36, for controlling the energization of solenoid L1 and operation of the total revolutions counter comprises a transistor switching device Q1 and a biasing network. The emitter and collector of the switching device Q1 are series-connected with the solenoid L1 across the output terminals of the battery 26 and when in a conducting state will energize the solenoid L1. Connected to the base of the transistor Q1 is a resistor R3 with a biasing capacitor C1 connected in shunt relationship to the resistor R3 and emitter-base connection of transistor Q1. The capacitor C1 is connected in circuit with the power source 26 through a series connected resistor R4 and the selectively operable contacts of the sensor means 11. With the contacts of the sensor means 11 in an open circuit configuration, the transistor Q1 will be in a nonconducting state when the capacitor C1 is fully discharged and the emitter-base bias is zero. Closing of the contacts of the sensor means 11 will complete the circuit to the power source 26 and result in current flow through the seriesconnected resistor R4 and capacitor C1. This current flow results in charging of the capacitor C1 and, as the charge on the capacitor C1 reaches a predetermined voltage value, the base-emitter bias of the transistor Q1 will reach a value where the transistor Q1 is no longer cut off and will be switched to a conducting state. In this conducting state, current will flow through the collector-emitter and through the solenoid coil L1 resulting in energization of the coil and initiation of operation of the counter 22. Transistor Q1 will remain in a conducting state as long as the contacts of the sensor means 11 are maintained closed and the base-emitter bias remains above the cutoff point. Opening of the contacts of the sensor means 11 will not result in immediate return of transistor Q1 to a nonconducting state as a result of the time constant of the biasing network. Opening of the contacts of the sensor means 11 will disconnect the biasing network from the power source 26 and the capacitor C1 will then discharge through the resistor R3 and the base-emitter of the transistor Q1. The time of discharge is determined by the component values of the resistance R3, resistance of the transistor Q1 and capacitor C1. This delay time is necessary to assure operation of the counter 22 as a finite time is required for energization of the coil L1 and mechanical actuation of the mechanism. As the voltage of the capacitor C1 is reduced to the cut-off point of the transistor Q1, the transistor will return to a nonconducting state thereby disconnecting the solenoid coil L1 from the battery 26 and permitting the coil to discharge through the diode CR1. As the solenoid coil L1 becomes discharged, the operation of the counter 22 will be concluded to record a motion cycle. This operation of the electronic switching apparatus 36 will be repeated each time the magnetic actuating device 12 passes the sensor means 11 and closes the sensors contacts and result in recordation of a motion cycle by the total revolutions counter 22.

The shunt-connected switching device 28 comprises a transistor Q2 having the collector thereof connected to the low voltage side of the current-limiting resistor R1 and the emitter connected to the ground circuit or negative terminal of the power source 26. The base of the transistor Q2 is connected to the six-second delay circuit 30 which is selectively operable to maintain the baseemitter bias voltage at a value below the cut-off point or to alternatively maintain the base-emitter bias voltage at a value above the cut-E point. In the state of operation where the bias voltage is below cut-oil, the transistor Q2 'will be nonconducting and when the bias voltage is above cut-oil, the transistor will be in a current-conducting state and voltage signal pulses produced by the sensor means 11 will be shunted to ground.

The switching device 27 which is series-connected with the mix counter 23 also includes a transistor switching device Q3 for effecting the operation thereof. The base of the switching transistor Q3 is connected to the lowvoltage side of the current-limiting resistor R1 and the emitter is connected through a resistor R to the negative terminal of the power source 26. The collector is connected to the fifteen-second delay circuit 29 which is selectively operable to alternatively connect the collector to the B-plus of the regulated power supply. When the fifteen-second delay circuit 29 is in an operating state wherein the collector of transistor Q3 is disconnected from the B-plus power supply the transistor will be effectively nonconductive and will represent an open circuit to voltage signal pulses received through the resistor R1. However, when the delay circuit 29 is in an operating state connecting the collector of transistor Q3 to the B-plus power supply, the transistor Q3 will be in an operating state where a voltage signal pulse applied to the base of the transistor Q3, and which is of a sufiicient magnitude to bias the transistor above the cut-oil point, will result in current conduction through the collector-emitter and resistor R5.

A current flow through the resistor R5 will produce a voltage drop across the resistor which will be operative to control the electronic switching circuit 37 associated with the solenoid L2. This switching circuit 37 includes a transistor Q4 having the collector and emitter terminals series-connected with the solenoid coil L2 across the power source 26 and a base connected through a resistor R6 and series-connected rectifier device CR4 to the emitter of transistor Q3. Thus, a voltage developed across the resistor R5 will form a base-emitter bias for Q4 and current conduction through the transistor will result when this bias voltage is above the cut-off value. The application of a signal voltage pulse to the base of the series switching device transistor Q3 produces a bias voltage for transistor Q4 which is above the cut-off value resulting in current conduction through transistor Q4 and the solenoid coil L2 and thus initiate operation of the respective mix counter device 23. Removal of the voltage signal pulse previously applied to the base of the transistor Q3 will result in biasing of the transistor below the cut-off point and the transistor will return to a nonconducting state thereby effectively eliminating any voltage drop across resistor R5. Elimination of the voltage drop across R5 will result in elimination of the bias voltage applied to the base of the transistor Q4. Transistor Q4 will then return to a nonconducting state. As transistor Q4 becomes nonconducting, the solenoid coil L2 will complete its actuation cycle and record a motion cycle on the counter device 23. Upon return of transistor Q4 to a nonconducting state, the solenoid coil L2 will discharge through its shunt-connected rectifier device CRZ. Since the solenoid coil L2 and associated actuating means require a finite operating time to assure positive operation, a capacitor C2 is connected across the series-connected resistor R6 and base-emitter terminals of transistor Q4 to provide a biasing network. The capacitor C2 will be charged to the voltage across the resistor R5 and this charge on the capacitor C2 will maintain the base-emitter biasing voltage above the cut-off point of thetransistor Q4 and thus maintain conduction through the transistor for a predetermined time after the voltage drop across R drops below the cut-off point for transistor Q4 as determined by discharge of the capacitor C2 through the transistor. Capacitor C2 will then dis- 8 charge through the resistance R6 connected to the base of the transistor Q4 and transistor Q4 will become nonconducting when the bias voltage has dropped below the cut-off point.

Each of the delay circuits 29 and 30 is of a similar construction and incorporates a resistance-capacitance (RC) timing network which operatively controls a trigger circuit eifecting the alternate operation of the reSpective switch devices 27 and 28 between the conducting and nonconducting states. Forming the timing network of the six-second delay circuit 30 is a timing capacitor C3 and the series-connected resistances R7 and R8 which are connected in shunt relationship to the capacitor C3. One of the resistances R8 is preferably of an adjustable type to facilitate precise adjustment of the timing interval determined by the resistance-capacitance (RC) time constant of this circuit. A common terminal of the RC netis connected to the regulated B-plus power supply while the opposite common terminal is connectable to the negative terminal of the battery 26 through a current-blocking diode CR5 and the reset circuit 31. The reset circuit 31 functions as an electronic switch which is operable on receiving a voltage signal pulse through the sensor means 11 to complete a circuit from the capacitor C3 and its shunt-connected resistances R7 and R8 through the diode CR5 to the negative terminal of the power supply. When the reset circuit 31 is in a current-conducting state, substantially the entire B-plus power supply will be applied to the capacitor C3 and result in charging of the capacitor to this voltage. There will be a finite voltage drop across the diode CR5 and the reset circuit 31 which, in the present embodiment, approximates eight-tenths of a volt. Thus, athe voltage applied to the capacitor C3 will be approximately 7.4 volts.

Also connected to the low-voltage side of the RC timing network formed by capacitor C3 and resistances R7 and R8 is a transistor Q5 of the trigger circuit for the six-second delay circuit. Interconnecting the base of transistor Q5 with the RC timing network is a blocking diode CR6 having the cathode thereof connected to the base of the transistor Q5. A voltage-dropping resistor R9 connects the collector of transistor Q5 to the B-plus power supply while the emitter is connected to the center point of a voltage-divider network formed by the series-connected resistances R10 and R11. Also connected to the collector of transistor Q5 is the base of the second transistor Q6 of this trigger circuit. The collector of transistor Q6 1s connected directly to the B-plus power supply while the emitter is connected to one end of the voltage-divider resistances R10 and R11. The opposite end of the voltagedivider network is connected to the negative terminal of the power supply 26. A coupling resistor R12 connects the emitter of transistor Q6 to the base of the transistor switching device Q2. Connected in shunt relationship with the resistor R9 is capacitor C4 which forms a timing clrcuit therewith.

In a quiescent state of operation of the six-second delay circuit 30 with the B-plus power supply energized and where either the sensor means 11 has not been actuated or more than six seconds have elapsed since actuation, the capacitor C3 will have at least been discharged to the extent that the base-emitter bias voltage transistor Q5 will be above the cut-01f point and transistor Q5 will be switched to a current conducting state. In the instance where capacitor G3 has been fully discharged, the base of transistor Q5 will be effectively connected to the regulated B-plu-s power supply. With transistor Q5 conducting, a current will flow through the resistance R9 and produce a voltage drop across this resistor and across resistance R10. Resistances R9 and R10 are selected such that the value of the resistance R9 is substantially greater than R10 and the majority of the voltage will be dropped across resistance R9. Transistor Q6 will not be conducting at this point. and the base of the switching device transistor Q2 will be effectively at the voltage which is dropped across the resistance R10. Through appropriate selection of the resistances R9 and R10, this voltage drop will be below the cut-off biasing voltage for the base-emitter of transistor Q2 and this transistor will then be in a nonconducting state.

Operation of the transistor Q2 in a nonconducting state will continue until the six-second delay circuit 30 will have been operated to return it to an initial operating state for determination of a time interval. Return of the delay circuit 30 to an initial operating state is effected by the operation of the reset circuit 31. As previously described, the reset circuit 31 will function on closing of the contacts of the sensor means 11 to become current conducting through the transistor Q9 and the low-voltage common terminal of the RC timing network formed by the capacitor C3 and resistances R7 and R8 will be effectively connected to the negative terminal of the power supply. The base of the transistor Q will also be effectively connected to the negative terminal of the power supply and will have a base-emitter bias below the cutotfpoint and Q5 will become nonconducting. As currentilow through the transistor Q5 ceases, the voltage drop across resistance R9 due to collector current of transistor Q5 will be reduced to zero with the result that the base of transistor Q6 will be effectively connected to the B-plus power supply voltage by resistor R9. Although the current flow through the transistor Q5 will cease substantially instantaneously, the base of transistor Q6 will not be effectively connected to the positive B-plus voltage instantaneously as a consequence of the delaying operation of capacitor C4. The resistance R9 forms a discharge circuit for the capacitor C4 which had been previously charged to the voltage drop across the resistances R9 and will main the transistor Q6 in a nonconducting state for a period of time as determined by the resistance capacitance values of this time delay circuit.

When the charge on the capacitor C4 has been reduced to a value where the base-emitter bias of transistor Q6 has been increased to a value above the cut-01f point, the transistor Q6 will become conducting and current will flow through the emitter-collector and the voltage divider network formed by the resistances R10 and R11. Except for the small voltage drop across the transistor Q6 itself, the B-plus power supply voltage will appear across the seriesconnected resistors R10 and R11 with the consequent result that the base emitter bias of the switching device transistor Q2 will be approximately at the value of the B-plus power supply voltage and well above its cut-off point. Thus, the switching device transistor Q2 will be transferred to a current-conducting state and current may flow through the transistor from the low voltage terminal of the resistor R1 to the negative terminal of the power supply 26.

Concurrently with the transfer of the switching device transistor Q2 to a current-conducting state, the capacitor C3 of the RC timing network will be charged to substantally the B-plus power supply voltage for initiation of the determination of a timing interval. This timing interval is initiated subsequent to the time that the contacts of the sensor means 11 have again opened and at the time that the reset circuit 31 has again become nonconducting thereby disconnecting the common terminal of capacitor C3 and resistors R7 and R8 from the negative terminal of the battery 26. This charging operation is concluded after the transistor Q2 has been switched to a conducting state. At this time the capacitor C3 will be disconnected from the charging circuit formed by the power supply 26 and will discharge through the resistances R7 and R8 at a rate determined by the value of the resistances. After the capacitor C3 has discharged to a voltage value where the base-emitter bias of the transistor Q5 is above the cutofi point, the transistor Q5 will again be conducting and the delay circuit will return to its initial state of operation. In this initial state of operation, with the transistor Q5 conducting, the transistor Q6 will be cut oif and the base-emitter bias of the switching device transistor Q2 will again be the voltage dropped across resistance R10 and the transistor Q2 will be cut off and switched to a nonconducting state. Thus, the operation of the switching device transistor Q2 is determined by the discharge of the timing network formed by the capacitor C3 and the resistances R7 and R8. Component values of the resistances R7 and R8 and the timing capacitor C3 are determined by the time interval during which it is desired to maintain the switching device 28 in a current-conducting state. In the present embodiment, this time interval is of the order of six seconds and accordingly the capacitor C3 will discharge to a voltage value where the transistor Q5 will become conducting at six-seconds after the conclusion of the charging operation.

The fifteen-second delay circuit 29 is similar to the sixsecond delay circuit. As can be seen by reference to FIGURE 3, the fifteen-second delay circuit 29 also includes a resistance-capacitance (RC) timing network comprising a capacitor C5 and shunt-connected resistances R13 and R14. Resistor R14 may also be of the adjustable type to facilitie precise adjustment of the timing interval. A common terminal of the RC timing network is connected to the B-plus power supply and a second or low voltage common terminal of the RC timing network is connected to the reset circuit 31 through a blocking diode CR7. The low-voltage terminal of the RC timing network is also connected to the base of a transistor Q7 of the delay circuit through a blocking diode CR8. The colector of transistor Q7 is connected to the regulated B-plus power supply through a voltage-dropping resistor R15 and the emitter is connected to the center point of a voltage divider network formed by the series-connected resistances R17 and R18 and having one terminal connected to the ground circuit. A second transistor Q8 of this delay circuit has the base connected to the collector of transistor Q7 through a resistor R16. The collector of transistor Q8 is connected to the regulated B-plus power supply and the emitter of Q8 is connected to the opposite terminal of the voltage divider network R17 and R18. Connected across the base-collector of transistor Q8 and in shunt relationship to the resistances R15 and R16 is a capacitor C6. The capacitor C6 functions to delay switching of transistor Q8 to conducting state for a predetermined time interval. Also connected to the emitter of transistor Q8 is the collector of the switching transistor Q3.

In a quiescent state of operation of the fifteen-second delay circuit 29 with the B-plus power supply energized and where either the sensor means 11 has not been actuated or more than fifteen-seconds have elapsed since actuation, the capacitor C5 will have discharged through the resistances R13 and R14 to the point where the base-emiter bias of transistor Q7 will be of sufficient value to permit current conduction through the transistor. With current flowing through transistor Q7, a voltage drop will appear across resistances R15 and R17 and the component values of these two resistances are selected such that only a nominal voltage will appear across resistor R17. With substantially the entire regulated B-plus power supply voltage dropped across resistor R15, the baseemitter bias of transistor Q8 will be well below the cutoff point and transistor Q8 will be nonconducting. The collector voltage of transistor Q3 will be that voltage appearing across the voltage divider network resistors R17 and R18 and, in this operating state, the collector voltage is effectively the voltage drop across resistor R17 due to current flow through transistor Q7. Since this Voltage is only a nominal value, transistor Q3 will be essentially nonconducting irrespective of any voltage applied to the combination of resistances R1 and R5 and the baseemitter junction of transistor Q3.

Closing of the contacts of the sensor means 11 will actuate the reset circuit 31 and result in charging of the capacitor C5 of the RC timing network of the delay circuit 29 for initiating determination of a fifteen second time interval. Charging of the capacitor C by means of operation of the reset circuit 31 in an identical manner as described in conjunction with the six-second delay circuit 30 will result in a decrease of the base-emitter bias of Q7. Effectively, the base-emitter bias voltage of Q7 will be zero and Q7 will be nonconducting. Capacitor C6 which has been previously charged to the voltage drop across R15 will maintain'transistor Q8 in a nonconducting state for a time interval as determined by the discharge of capacitor C6 through resistances R15 and R16. After the capacitor C6 has been discharged to a value where the base-emitter bias of transistor Q8 will be above the cut-off point, transistor Q8 will be switched to a current-conducting state and substantially the entire B-plus power supply voltage will appear across resistances R17 and R18. As this time the collector of the switching device transistor Q3 will be at the B-plus power supply voltage and Q3 may then become conducting at any time a positive voltage pulse is applied to the base to increase the base-emitter bias of Q3 to a value above the cut-off point as by subsequent closing of the contacts of the sensor 11 for recording a motion cycle which is effective as a mixing cycle. The switching device transistor Q3 will remain in this operating state for a timed interval of fifteen seconds after the reset circuit 31 has returned to a nonconducting state. After elapse of fifteen-seconds as determined by discharge of capacitor C5 to a voltage value where the base-emitter bias of transistor Q7 is again above the cut-off point, Q7 will become conducting and the delay circuit will operate to return the switching transistor Q3 to a nonconducting state and thereby prevent passage of a voltage signal pulse and the mix counter 23 will not be actuated to record a motion cycle having a frequency less than the specified minimum.

The time-delay resulting from operation of capacitor C6 in the fifteen-second delay circuit 29 is efiective, after the elapse of a fifteen-second time interval or at any time when transistor Q3 is nonconducting, to prevent switching of transistor Q3 to a conductive state immediately after the occurrence of a voltage signal pulse and thus preventing passage of the signal pulse to the electronic switching circuit 37 and consequent operation of the mix counter 23. This time-delay prevents a voltage signal pulse occurring after a fifteen-second interval from being recorded by the mixing revolutions counter 23 but does not prevent the reset circuit 31 from operating to perform the resetting function for each of the delay circuits 29 and 30. A time-delay is also introduced into the operation of the six-second delay circuit 30 as a result of the operation of the capacitor C4 but this delay is only of consequence during the time interval of six to fifteen seconds after initiation of a timing interval. During this time interval, the switching device transistor Q2 will be in a nonconducting state and the occurrence of a voltage signal pulse to the reset circuit 31 will not be effective in immediately switching transistor Q2 to a conducting state. This delay results from the operation of capacitor C4 and is necessary to provide sufiicient time for the voltage signal pulse to act on switching device transistor Q3 and efiect operation of the mixing revolutions counter 23. Resistance R9 and R15 and capacitors C4 and C6 are of the same nominal values and, consequently, each time-delay circuit formed by the respective elements would have substantially the same delay time. However,

these delay times may differ slightly in actual practice as the result of slight diiferences in component values and in assembly into a circuit. If the delay time of the C6-R15 combination were slightly less than the delay time of the C4R9 combination, a voltage signal pulse applied to the circuit after the elapse of fifteen seconds from initiation of the time interval and which is of a duration greater than the delay time of the C6-R15 combination could result in operation of the mixing revolutions counter 23. Such undesired operation is prevented by incorporation of additional resistance R16 in the C6-R15 combination to assure that the delay time of this circuit will be greater and that the six-second delay circuit 30 will return transistor Q2 to a conducting state before Q3 becomes conducting and thereby shunt the signal to ground.

The resetting function for the delay circuits 29 and 30 is performed by the reset circuit 31. In the present embodiment, the reset circuit 31 comprises a transistor Q9 having the collector-emitter terminals connected in series with a resistor R19 across the unregulated power source for operation as an electronic switch. The cathodes of the diodes CR5 and CR7 are connected to the collector of transistor Q9 and connect the respective delay circuits 30 and 29 to the reset circuit 31. A resistor R20 connects the base of transistor Q9 to the junction of resistor R4 and a terminal of the sensor means 11 to provide a base-emitter bias. The transistor Q9 is nonconducting when the base-emitter bias is below the cut-off point as is the case when the sensor means 11 is open. With the transistor Q9 nonconducting the collector terminal will be effectively at the power supply voltage and each of the RC timing circuits will be effectively disconnected from the negative power supply terminal. Closing of the contacts of the sensor means 11 will result in biasing of transistor Q9 above the cut-off point Q9 will be conducting. While conducting, the collector-emitter resistance of Q9 is nominal and substantiall the entire power supply voltage will be dropped across R19 and each of the RC timing circuits will be eifectively connected to the negative or ground of the circuit for the charging operation. When the contacts of the sensor means 11 again open, the base-emitter bias will be removed and Q9 will return to a nonconducting state. This will complete the resetting operation.

Also included in this apparatus is an indicator lamp circuit 34 which controls the operation of an indicator lamp 35. This circuit operates to cause the lamp 35 to be illuminated during operation of the mixer drum 14 at a rotational speed within the accaptable range to provide a visual indication to the vehicle operator of such operation. The indicator lamp circuit 34 includes a silicon controlled rectifier (SCR) Q10 which is connected in series with the lamp 35 across the power supply and operates as a switch to control illumination of the lamp. A resistor R21 is also connected in series with the SCR Q10. Connected between the gating terminal of the SCR Q10 and the ground circuit is a voltage dropping resistor R22 which is effective in providing the gating voltage necessary to turn on Q10. The source of this gating voltage is the capacitor C2 of the electronic switching circuit '37 controlling the operation of the mixing revolutions counter 23. A current-limiting resistor R23 connected between the positive terminal of capacitor C2 and the gating terminal of the SCR Q10 forms a voltage divider network with resistor R22 to provide the gating voltage to turn on Q10 each time the mixing revolutions counter 23 is actuated to record a mix cycle. Once Q10 has been switched to a current conducting state, Q10 will remain current conducting for continued illumination of the indicator lamp 35 until the SCR Q10 is turned off by making the anode relatively negative to the cathode.

This turn-off function is elfected by the reset circuit 31 through a capacitor C7 interconnecting the anode of the SCR Q10 with the collector terminal of transistor Q9. With the SCR Q10 initially not conductive, the anode will effectively be at the unregulated power supply voltage and operation of the reset circuit 31 to make transistor Q9 conductive would not affect operation of the lamp circuit 34 other than to charge the capacitor C7 to the power supply voltage with the plate connected to the SCR anode being made relatively positive. If the voltage signal pulse applied to the reset circuit 31 is not transmitted by transistor Q3 to charge capacitor C2, the SCR Q10 will not be switched to a conducting state and the operation will continue without the lamp 35 being illuminated. If a voltage signal pulse is transmitted by transistor Q3 to charge capacitor C2 to a voltage which will result in operation of the mixing revolution counter 23, a gating voltage will also be applied to the SCR Q10, and Q will be switched to a conducting state resulting in the lamp 35 being illuminated. There will be only a nominalvoltage drop across the SCR and the plate of the capacitor C7 connected to the anode will be elfectively at ground'p otential. While Q9 is conducting the plate of the capacitor C7 connected to its collector terminal -will also be effectively at ground potential but, when Q9 ceases tofconduct, this plate of the capacitor C7 will be effectively. connected to the positive terminal of the power source and the capacitor will be effectively charged to the power supply voltage. This will not affect the SCR Q10 'which will continue to conduct and the lamp 35 will remain illumifnated. Closing of the contacts of the sensor means 11 at the conclusion of the next succeeding motion cycle will now effect the turn-off function and return Q10 to a nonconducting state. Closing of the sensor means contacts results in operation of the reset circuit 31 and Q9 will again be conductive. This effectively connects the plate of capacitor C7 connected to the'collector terminal to ground. Since capacitor C7 had been previously charged with plate connected to the collector relatively positive, the anode of the SCR Q10 will be made relatively negative for a period of time before C7 will be discharged. With the anode relatively negative, the SCR Q10 will cease to conduct and no current will flow through the "lamp 3,. If the voltage signal pulse actuating the reset circuit 31 to turn off the SCR Q10 is an effective mix cycle, another gating voltage will be applied to the SCR whichqwill be effective to again turn on the SCR as soon as the capacitor has been effectively discharged. The time involved in the turn-off operation is relatively short and the lamp 35 will appear to remain continuously illuminated. If the voltage signal pulse does not occur within the six to fifteen-second interval, the lamp 35 will not continue to be illuminated.

In the present embodiment of the apparatus, the sensor means 11 comprises a reed switch which is responsive to a magnetic field of predetermined strength and magnetic actuating device 12 comprises a permanent magnet. The sensor means is normally open-circuited but the contacts will close in response to the presence of a proximate magnetic field of predetermined strength. The permanent magnet is of a suitable strength and mounted in a housing to effect operation of sensor means 11 as desired. It is to be understood, however, that other well known types of sensors may be utilized to effect the switching function of the reed switch and may be readily substituted therefor.

The counter apparatus of this invention provides a convenient means for accurately monitoring the operation of a ready-mix type concrete truck. By noting the recorded motion cycles as displayed by the total revolutions and mix revolutions counters at the time the mixer is charged with the materials and at the delivery point, it is a simple matter to determine whether a specific batch of concreteis acceptable according to the particular specifications. An inspector at the batching plant would note the readings at the time the mixer is charged with the materials and, during transit, the truck operator would be able to determine the progress of the mixing operation and appropriately adjust the operation. A second inspector at the delivery point would note the counter readings and, through comparison with the readings at the starting time, determine acceptability of the concrete.

It is readily apparent that the? counter apparatus of this invention provides an accurate determination of motion cycles which are within a predetermined frequency range. The electronic switching devices controlling the operation of a visual display counter provide positive control and prevent erroneous actuation of the counter. Uailization of electronic circuits having solid state electronic components provides a counter apparatus which is of rugged construction and substantially unaffected by the environmental conditions.

According to the provisions of the patent statutes, the principles of this invention have been explained and have been illustrated and described in what is now considered to represent the best embodiment. However, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Having thus described this invention, what is claimed 1. A counter apparatus for determining motion cycles which are of a frequency within a selected range comprising sensor means responsive to a cyclic movement, counter means for cumulatively recording cyclic movements sensed by said sensor means, and circuit means electrically interconnected with said sensor means and counter means and being operable to permit actuation of said counter means in response to cyclic movement sensed by said sensor means having a frequency within a selected range, said circuit means includes an electronic timing circuit operable to prevent actuation of said counter means for motion cycles having a frequency less than a predetermined minimum or greater than a predetermined maximum, said electronic timing circuit includes a first electrically discharging network circuit controlling first normally closed switch means series connected with said counter means and a second electrically discharging network circuit controlling second normally closed switch means connected in shunt relationship with said series connected first switch means and counter means, said first and second discharging network circuits being operable to open the respectively controlled first and second switch means after elapse of a predetermined time interval after initiation of a motion cycle, said first discharging network circuit being operable after a relatively greater time interval than said second discharging network circuit whereby only those motion cycles which are of a time duration which terminates between the operation of said first and second discharging network circuits are effective in operating said counter means.

2. A counter apparatus according to claim 1 which includes additional counter means for cumulatively recording cyclic movements sensed by said sensor means,

said additional counter means being directly connected with and responsive to said sensor means for recording all cyclic movement sensed by said sensor means.

3. A counter apparatus according to claim 1 in which the predetermined minimum is of the order of four cycles per minute and the predetermined maximum is of the order of ten cycles per minute.

4. A counter apparatus according to claim 1 which includes a source of electrical power suitable for operation of said counter means and said circuit means and wherein said sensor means is operable to selectively connect said counter and circuit means to said electrical power source for actuation of said counter means and initiation of operation of said circuit means.

5. A counter apparatus according to claim 4 wherein said sensor means comprises a normally open, magneticfield-responsive electrical switch.

6. A counter apparatus according to claim 1 wherein said first and second switch means comprise electronic switching devices and said first and second electrically discharging network circuits each including a parallel connected resistance-capacitance circuit electrically interconnected with a respective switching device and operable on discharge of said capacitor to a predetermined value to transfer the respective switching device from an electrically conducting state to an electrically nonconducting state.

7. A counter apparatus according to claim 1 wherein said circuit means includes a charging and reset circuit network electrically interconnected with said first and second electrically discharging network circuits and in-' cluding an electricalpower source, said charging and reset circuit network being responsive to said sensor means and being operable on initiation of a motion cycle to transfer said first and second switch means to an electrically conducting state and to charge said discharging network circuits to a predetermined value through connection to said power source.

8. A counter apparatus according to claim 7 wherein said circuit means includes an indicator lamp circuit having an electricallyenergizable lamp and an electronic switching circuit with said lamp to control the energization of said lamp, said switching circuit being responsive to operation of said counter means to cause energization of said lamp for each motion cycle effective in operating said counter means, said switching circuit being interconnected with said reset circuit to effect deenergization of said lamp at the conclusion of a motion cycle.

'9. A .counter apparatus according to claim 1 wherein said circuit means includes visual indicator means o'perable in response to operation of said counter means to visually indicate such operation.

16 p 10. A counter apparatus according to claim 9 wherein s'aid visual indicator means includes an electrically energizable lamp and an electronic switching circuit connected with said lamp to control the energization of said lamp.

11. A counter apparatus according to claim 1 wherein said sensor means is disposed in operative relationship to a mixer drum for responding to cyclic movemen thereof.

References Cited UNITED STATES PATENTS 3,139,539 6/1964 Hewett 307-885 3,219,804 11/1965 Annable 235-92 3,277,284 10/ 1966- Cripe et a1. 235-92 3,235,811 2/1966 Steiger 329-103 MAYNARD R. WILBUR, Primary Examiner J. M. THESZ, 111., Assistant Examiner US. Cl. X.R. 235-103; 324-68 

